Advanced pulsed electro-acoustic system for space charge measurement

Fothergill, J.C.; Dissado, L. A.; Alison, J.; See, Alex

doi:10.1049/cp:20000532

Cited by 17 publications

(13 citation statements)

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“…Two different PEA systems were used, one of those allowing simultaneous measurement of the external current with a sensitivity of 10 -14 A [5]. Measurements were performed in air or in controlled atmosphere (nitrogen) at room temperature.…”

Section: Space Charge and External Current Measurementsmentioning

confidence: 99%

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Charge distribution and electroluminescence in cross-linked polyethylene under dc field

Teyssèdre

Laurent

Montanari

et al. 2001

J. Phys. D: Appl. Phys.

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This is the unspecified version of the paper.This version of the publication may differ from the final published version. between charge packet formation and propagation, and electroluminescence. Although the two phenomena are observed in the same field range, it is found that the onset of continuous EL follows the formation at the electrodes of positive and negative space charge regions that extend into the bulk prior to the propagation of charge packets. Charge recombination appears to be the excitation process of EL since oppositely charged domains meet in the material bulk. To gain an insight into specific light excitation process associated with charge packet propagation, electroluminescence has been recorded for several hours under fields at which charge packet dynamics were evidenced. It is shown that current and luminescence oscillations are detected during charge packet propagation, and that they are in phase. Mechanisms underlying EL and charge packets are further considered on the basis of these results. Permanent repository link2

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Section: Space Charge and External Current Measurementsmentioning

confidence: 99%

“…All space charge measurements were made simultaneously with the current in the external circuit [5,18].…”

Section: 32charge Profiles By Using a Progressive DC Stress Testmentioning

confidence: 99%

Charge distribution and electroluminescence in cross-linked polyethylene under dc field

Teyssèdre

Laurent

Montanari

et al. 2001

J. Phys. D: Appl. Phys.

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“…Space charge measurements were performed by the pulsed electro-acoustic technique [32] at various DC-voltages varying from ~10 to 180 kV/mm. Measurements were performed in air at room temperature.…”

Section: Space Charge Distribution Analysismentioning

confidence: 99%

Electroluminescence excitation mechanisms in an epoxy resin under divergent and uniform field

Griseri

Dissado

Fothergill

et al. 2002

IEEE Trans. Dielect. Electr. Insul.

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This is the unspecified version of the paper.This version of the publication may differ from the final published version. Permanent repository link: ABSTRACTElectroluminescence excitation mechanisms have been investigated in epoxy resin under divergent and uniform field situations. Metallic wires embedded in the resin were used to produce field divergence whereas film samples were metallised to obtain a uniform field. Electroluminescence under divergent field was stimulated by an impulse voltage. Light was emitted on the positive and negative fronts of the square pulses when the field exceeded 20 kV/mm at the wire surface, with equal intensity and without polarity dependence. There was evidence of space charge accumulation around the wires in multiple-pulse experiments. Charge injection and extraction occurring at both fronts of the pulse provide the condition for EL excitation. Further excitation of the EL during the plateau of the voltage pulse is prevented by the opposite field of the trapped charge. Field computation with and without space charge supports the proposed interpretation. A DC voltage was used for the uniform field experiments. A continuous level of electroluminescence is found at 175 kV/mm. Charging/discharging current measurements and space charge profile analyses using the pulsed electro-acoustic (PEA) technique were performed at different fields up to the EL level. Dipolar orientation generates a long lasting transient current that prevents the conduction level being reached within the experimental protocol (one hour poling time). The continuous EL emission is nevertheless associated with a regime where the conduction becomes dominant over the orientational polarization. Polarization and space charge contribute to the PEA charge profiles. Homo-charge injection at anode and cathode is seen at 20 kV/mm and a penetration of positive space charge in the bulk is detected above 100 kV/mm, suggesting an excitation of the continuous EL by bipolar charge recombination.2 INTRODUCTIONElectroluminescence (EL) will be defined in our context as the light emitted from a solid material when subjected to an electric stress. It results from the radiative relaxation of excited states that are created by the application of the field. These states can be delocalized when dealing with EL of semiconducting materials [1,2], or highly localized when dealing with large band gap materials such as polymers used as insulation in electrical engineering [3]. In the latter case, it has been known for a long time that the existence of internal gas-filled cavities can also be at the origin of a light emission due to the excitation of gaseous molecules accompanying discharge occurrence [4]. In this paper, we will focus on the investigation of the light emitted by the material by taking care not to introduce any internal cavities of a size suitable to sustain partial discharges. This needs careful control during sample preparation.EL detection in a given material is evidence of the generation of excited states of energy bet...

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“…The principle of the pulsed-electro acoustic system (PEA) is described in many studies (Fothergill et al 2000;Liu et al 1993). The PEA system (PEANUT, made by Five Lab) used in this study has a pulse width of 5 ns.…”

Section: Fig 2 Measurement Equipment Used In the Pea Methodsmentioning

confidence: 99%

Space Charge Behavior in Oil-Impregnated Insulation Paper Reinforced with Nano-TiO2

Liao¹,

Lv²,

Yang³

et al. 2013

BioResources

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a Oil-impregnated insulation paper is widely used in power transformers, and the insulation properties of oil-impregnated insulation paper play an important role in the reliability of power equipment. The formation and dynamics of space charge can affect the performance of insulation material. However, methods to improve the space charge distribution in oil-impregnated insulation paper are rarely reported. In this paper, space charge behavior in oil-impregnated insulation paper has been investigated using the pulsed electro-acoustic (PEA) technique. A series of measurements was applied when the oil-impregnated insulation paper reinforced with different nano-TiO 2 contents was subjected to various electric field strengths. The accumulation and decay of space charge are discussed, and the internal electric field strength distribution of oilimpregnated insulation paper is analyzed. The test results show that the space charge distribution is improved and the distortion rate of the internal electric field strength is reduced by adding nano-TiO 2 to the oilimpregnated insulation paper. The results show that the proposed method offers a new way to improve the properties of oil-impregnated insulation paper.

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Advanced pulsed electro-acoustic system for space charge measurement

Cited by 17 publications

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Charge distribution and electroluminescence in cross-linked polyethylene under dc field

Charge distribution and electroluminescence in cross-linked polyethylene under dc field

Electroluminescence excitation mechanisms in an epoxy resin under divergent and uniform field

Space Charge Behavior in Oil-Impregnated Insulation Paper Reinforced with Nano-TiO2

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